This invention relates to the use of antigestagens for shifting the endometrial maturation in the post-ovulatory phase (luteal phase) with reference to the nidation-point.
In recent years, especially in the Western World, a greatly increasing proportion of women find themselves confronted with the problem of undesired sterility. For those women whose sterility is associated with a completely irremovable blockage of the fallopian tubes, a recent gynaecological-embryological technique, first successfully carried out in 1977/1978 by the Britons, Patrick Steptoe and Robert Edwards, has raised hopes for the fulfillment of their desire to bear children. A presupposition of this technique is that at least one of the patient's ovaries as well as her uterus is able to function.
In this process ripe egg-cells are first removed laparoscopically from one of the ovaries and subsequently fertilized in vitro. After the extra-corporeal fertilization, the embryo (zygote) is grown in a culture medium, and then, after about 48 to 72 hours, is implanted in the uterus of the woman.
In this method of therapy of in vitro fertilization and embryo transfer, which now has been used world wide, only a disapointingly small number of human embryos has survived. The main reason for the low number of successes is that the fertilized ova experiences retarded growth in in vitro culture so that a desynchronization occurs between embryo implantation and endometrium maturation.